﻿using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Net;
using System.IO;
using System.Web;
using System.Text.RegularExpressions;

namespace Utils
{
    /// <summary>
    /// 网络工具类。
    /// </summary>
    public sealed class WebUtils
    {
        private static int _timeout = 100000;

        /// <summary>
        /// 请求与响应的超时时间
        /// </summary>
        public static int Timeout
        {
            get { return _timeout; }
            set { _timeout = value; }
        }

        /// <summary>
        /// 执行HTTP POST请求。
        /// </summary>
        /// <param name="url">请求地址</param>
        /// <param name="parameters">请求参数</param>
        /// <returns>HTTP响应</returns>
        public static string DoPost(string url, IDictionary<string, string> parameters)
        {
            HttpWebRequest req = GetWebRequest(url, "POST");
            //req.ContentType = "application/x-www-form-urlencoded;charset=utf-8";

            byte[] postData = Encoding.UTF8.GetBytes(BuildQuery(parameters));
            Stream reqStream = req.GetRequestStream();
            reqStream.Write(postData, 0, postData.Length);
            reqStream.Close();

            HttpWebResponse rsp = (HttpWebResponse)req.GetResponse();
            Encoding encoding = Encoding.GetEncoding(rsp.CharacterSet);
            return GetResponseAsString(rsp, encoding);
        }

        /// <summary>
        /// 执行HTTP GET请求。
        /// </summary>
        /// <param name="url">请求地址</param>
        /// <param name="parameters">请求参数</param>
        /// <returns>HTTP响应</returns>
        public static string DoGet(string url, IDictionary<string, string> parameters)
        {
            if (parameters != null && parameters.Count > 0)
            {
                if (url.Contains("?"))
                {
                    url = url + "&" + BuildQuery(parameters);
                }
                else
                {
                    url = url + "?" + BuildQuery(parameters);
                }
            }

            HttpWebRequest req = GetWebRequest(url, "GET");
            req.ContentType = "application/x-www-form-urlencoded;charset=utf-8";

            HttpWebResponse rsp = (HttpWebResponse)req.GetResponse();
            Encoding encoding = Encoding.GetEncoding(rsp.CharacterSet);
            return GetResponseAsString(rsp, encoding);
        }

        ///// <summary>
        ///// 执行带文件上传的HTTP POST请求。
        ///// </summary>
        ///// <param name="url">请求地址</param>
        ///// <param name="textParams">请求文本参数</param>
        ///// <param name="fileParams">请求文件参数</param>
        ///// <returns>HTTP响应</returns>
        //public string DoPost(string url, IDictionary<string, string> textParams, IDictionary<string, FileItem> fileParams)
        //{
        //    // 如果没有文件参数，则走普通POST请求
        //    if (fileParams == null || fileParams.Count == 0)
        //    {
        //        return DoPost(url, textParams);
        //    }

        //    string boundary = DateTime.Now.Ticks.ToString("X"); // 随机分隔线

        //    HttpWebRequest req = GetWebRequest(url, "POST");
        //    req.ContentType = "multipart/form-data;charset=utf-8;boundary=" + boundary;

        //    Stream reqStream = req.GetRequestStream();
        //    byte[] itemBoundaryBytes = Encoding.UTF8.GetBytes("\r\n--" + boundary + "\r\n");
        //    byte[] endBoundaryBytes = Encoding.UTF8.GetBytes("\r\n--" + boundary + "--\r\n");

        //    // 组装文本请求参数
        //    string textTemplate = "Content-Disposition:form-data;name=\"{0}\"\r\nContent-Type:text/plain\r\n\r\n{1}";
        //    IEnumerator<KeyValuePair<string, string>> textEnum = textParams.GetEnumerator();
        //    while (textEnum.MoveNext())
        //    {
        //        string textEntry = string.Format(textTemplate, textEnum.Current.Key, textEnum.Current.Value);
        //        byte[] itemBytes = Encoding.UTF8.GetBytes(textEntry);
        //        reqStream.Write(itemBoundaryBytes, 0, itemBoundaryBytes.Length);
        //        reqStream.Write(itemBytes, 0, itemBytes.Length);
        //    }

        //    // 组装文件请求参数
        //    string fileTemplate = "Content-Disposition:form-data;name=\"{0}\";filename=\"{1}\"\r\nContent-Type:{2}\r\n\r\n";
        //    IEnumerator<KeyValuePair<string, FileItem>> fileEnum = fileParams.GetEnumerator();
        //    while (fileEnum.MoveNext())
        //    {
        //        string key = fileEnum.Current.Key;
        //        FileItem fileItem = fileEnum.Current.Value;
        //        string fileEntry = string.Format(fileTemplate, key, fileItem.GetFileName(), fileItem.GetMimeType());
        //        byte[] itemBytes = Encoding.UTF8.GetBytes(fileEntry);
        //        reqStream.Write(itemBoundaryBytes, 0, itemBoundaryBytes.Length);
        //        reqStream.Write(itemBytes, 0, itemBytes.Length);

        //        byte[] fileBytes = fileItem.GetContent();
        //        reqStream.Write(fileBytes, 0, fileBytes.Length);
        //    }

        //    reqStream.Write(endBoundaryBytes, 0, endBoundaryBytes.Length);
        //    reqStream.Close();

        //    HttpWebResponse rsp = (HttpWebResponse)req.GetResponse();
        //    Encoding encoding = Encoding.GetEncoding(rsp.CharacterSet);
        //    return GetResponseAsString(rsp, encoding);
        //}

        public static HttpWebRequest GetWebRequest(string url, string method)
        {
            HttpWebRequest req = (HttpWebRequest)WebRequest.Create(url);
            req.ServicePoint.Expect100Continue = false;
            req.Method = method;
            req.KeepAlive = true;
            req.UserAgent = "Top4Net";
            req.Timeout = _timeout;
            return req;
        }

        /// <summary>
        /// 把响应流转换为文本。
        /// </summary>
        /// <param name="rsp">响应流对象</param>
        /// <param name="encoding">编码方式</param>
        /// <returns>响应文本</returns>
        public static string GetResponseAsString(HttpWebResponse rsp, Encoding encoding)
        {
            Stream stream = null;
            StreamReader reader = null;

            try
            {
                // 以字符流的方式读取HTTP响应
                stream = rsp.GetResponseStream();
                reader = new StreamReader(stream, encoding);
                return reader.ReadToEnd();
            }
            finally
            {
                // 释放资源
                if (reader != null) reader.Close();
                if (stream != null) stream.Close();
                if (rsp != null) rsp.Close();
            }
        }

        /// <summary>
        /// 组装GET请求URL。
        /// </summary>
        /// <param name="url">请求地址</param>
        /// <param name="parameters">请求参数</param>
        /// <returns>带参数的GET请求URL</returns>
        public string BuildGetUrl(string url, IDictionary<string, string> parameters)
        {
            if (parameters != null && parameters.Count > 0)
            {
                if (url.Contains("?"))
                {
                    url = url + "&" + BuildQuery(parameters);
                }
                else
                {
                    url = url + "?" + BuildQuery(parameters);
                }
            }
            return url;
        }
        public static string WebResponseGet(HttpWebResponse webResponse)
        {
            StreamReader responseReader = null;
            string responseData = "";
            try
            {
                responseReader = new StreamReader(webResponse.GetResponseStream());
                responseData = responseReader.ReadToEnd();
            }
            catch
            {
                throw;
            }
            finally
            {
                webResponse.GetResponseStream().Close();
                responseReader.Close();
                responseReader = null;
            }
            return responseData;
        }
        /// <summary>
        /// 组装普通文本请求参数。
        /// </summary>
        /// <param name="parameters">Key-Value形式请求参数字典</param>
        /// <returns>URL编码后的请求数据</returns>
        public static string BuildQuery(IDictionary<string, string> parameters)
        {
            StringBuilder postData = new StringBuilder();
            bool hasParam = false;

            IEnumerator<KeyValuePair<string, string>> dem = parameters.GetEnumerator();
            while (dem.MoveNext())
            {
                string name = dem.Current.Key;
                string value = dem.Current.Value;
                // 忽略参数名或参数值为空的参数
                if (!string.IsNullOrEmpty(name) && !string.IsNullOrEmpty(value))
                {
                    if (hasParam)
                    {
                        postData.Append("&");
                    }

                    postData.Append(name);
                    postData.Append("=");
                    postData.Append(Uri.EscapeDataString(value));
                    hasParam = true;
                }
            }

            return postData.ToString();
        }

        /// <summary>
        /// 获取网站根目录的url
        /// </summary>
        /// <returns></returns>
        public static string GetRootURI()
        {
            string appPath = "";
            HttpContext httpCurrent = HttpContext.Current;
            HttpRequest httpRequest;
            if( httpCurrent != null )
            {
                httpRequest = httpCurrent.Request;

                string urlAuthority = httpRequest.Url.GetLeftPart(UriPartial.Authority);
                if( httpRequest.ApplicationPath == null || httpRequest.ApplicationPath == "/" )
                {
                    //直接安装在   Web   站点   
                    appPath = urlAuthority;
                }
                else
                {
                    //安装在虚拟子目录下   
                    appPath = urlAuthority + httpRequest.ApplicationPath;
                }
            }
            return appPath;
        }
        public static string ChangeHttpUrlToSSL(string filePath)
        {
            string rootPath = GetRootURI();
            rootPath = rootPath + "/" + filePath;
            if( rootPath.IndexOf("https") == -1 )
            {
                rootPath = rootPath.Replace("http", "https");
            }
            return rootPath;
        }
        public static string ChangSSLToHttp(string filePath)
        {
            string rootPath = GetRootURI();
            rootPath = rootPath + "/" + filePath;
            if( rootPath.IndexOf("https") != -1 )
            {
                rootPath = rootPath.Replace("https", "http");
            }
            return rootPath;
        }

        public static string GetOrderNum()
        {
            string time = DateTime.Now.ToString().Replace(" ", "").Replace("/", "").Replace(":", "").Replace("-", "");
            time = time.Substring(2, time.Length - 2).Insert(4, time.Remove(2));
            return "O" + time;
        }

        /// <summary>
        /// 获取用户真实IP地址
        /// </summary>
        /// <returns></returns>
        public static string GetRequestUserIp()
        {
            #region
            string ip =
                HttpContext.Current.Request.ServerVariables["HTTP_X_FORWARDED_FOR"];
            if( ip == null || ip.Length == 0 || ip.ToLower().IndexOf("unknown") > -1 )
            {
                ip = HttpContext.Current.Request.ServerVariables["REMOTE_ADDR"];
            }
            else
            {
                if( ip.IndexOf(',') > -1 )
                {
                    ip = ip.Substring(0, ip.IndexOf(','));
                }
                if( ip.IndexOf(';') > -1 )
                {
                    ip = ip.Substring(0, ip.IndexOf(';'));
                }
            }

            Regex regex = new Regex("[^0-9.]");
            if( ip == null || ip.Length == 0 || regex.IsMatch(ip) )
            {
                ip = HttpContext.Current.Request.UserHostAddress;
                if( ip == null || ip.Length == 0 || regex.IsMatch(ip) )
                {
                    ip = "0.0.0.0";
                }
            }
            return ip;
            #endregion
        }
    }
}
